1. Field of the Invention
This invention relates to novel aminocarbamates of polyalkylphenoxyalkanols. In a further aspect, this invention relates to the use of these compounds in fuel compositions to prevent and control engine deposits.
2. Description of the Related Art
It is well known that automobile engines tend to form deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports and intake valves, due to the oxidation and polymerization of hydrocarbon fuel. These deposits, even when present in relatively minor amounts, often cause noticeable driveability problems, such as stalling and poor acceleration. Moreover, engine deposits can significantly increase an automobile's fuel consumption and production of exhaust pollutants. Therefore, the development of effective fuel detergents or "deposit control" additives to prevent or control such deposits is of considerable importance and numerous such materials are known in the art.
For example, aliphatic hydrocarbon-substituted phenols are known to reduce engine deposits when used in fuel compositions. U.S. Pat. No. 3,849,085, issued Nov. 19, 1974 to Kreuz et al., discloses a motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range containing about 0.01 to 0.25 volume percent of a high molecular weight aliphatic hydrocarbon-substituted phenol in which the aliphatic hydrocarbon radical has an average molecular weight in the range of about 500 to 3,500. This patent teaches that gasoline compositions containing minor amounts of an aliphatic hydrocarbon-substituted phenol not only prevent or inhibit the formation of intake valve and port deposits in a gasoline engine, but also enhance the performance of the fuel composition in engines designed to operate at higher operating temperatures with a minimum of decomposition and deposit formation in the manifold of the engine.
U.S. Pat. No. 4,259,086, issued Mar. 31, 1981 to Machleder et al., discloses a detergent additive for fuels and lubricating oils which comprises the reaction product of an aliphatic hydrocarbon-substituted phenol, epichlorohydrin and a primary or secondary monoamine or polyamine. In addition, U.S. Pat. No. 4,048,081, issued Sep. 13, 1977 to Machleder et al., discloses a detergent additive for gasoline which is the reaction product of a polyisobutene phenol with epichlorohydrin, followed by amination with ethylene diamine or other polyamine.
Similarly, U.S. Pat. No. 4,134,846, issued Jan. 16, 1979 to Machleder et al., discloses a fuel additive composition comprising a mixture of (1) the reaction product of an aliphatic hydrocarbon-substituted phenol, epichlorohydrin and a primary or secondary mono- or polyamine, and (2) a polyalkylene phenol. This patent teaches that such compositions show excellent carburetor, induction system and combustion chamber detergency and, in addition, provide effective rust inhibition when used in hydrocarbon fuels at low concentrations. Amino phenols are also known to function as detergents/dispersants, antioxidants and anti-corrosion agents when used in fuel compositions. U.S. Pat. No. 4,320,021, issued Mar. 16, 1982 to R. M. Lange, for example, discloses amino phenols having at least one substantially saturated hydrocarbon-based substituent of at least 30 carbon atoms. The amino phenols of this patent are taught to impart useful and desirable properties to oil-based lubricants and normally liquid fuels.
In addition, polybutylamines have been taught to be useful for preventing deposits in the intake system of internal combustion engines. For example, U.S. Pat. No. 4,832,702, issued May 23, 1989 to Kummer et al., discloses fuel and lubricant compositions containing polybutyl or polyisobutylamine additives prepared by hydroformulating a polybutene or polyisobutene and then subjecting the resulting oxo product to a Mannich reaction or amination under hydrogenating conditions.
Polyether amine fuel additives are also well known in the art for the prevention and control of engine deposits. These polyether additives have a polyoxyalkylene "backbone", i.e., the polyether portion of the molecule consists of repeating oxyalkylene units. U.S. Pat. No. 4,191,537, issued Mar. 4, 1980 to Lewis et al., for example, discloses a fuel composition comprising a major portion of hydrocarbons boiling in the gasoline range and from 30 to 2,000 ppm of a hydrocarbyl polyoxyalkylene aminocarbamate having a molecular weight from about 600 to 10,000, and at least one basic nitrogen atom. The hydrocarbyl polyoxyalkylene moiety is composed of oxyalkylene units having from 2 to 5 carbon atoms in each oxyalkylene unit. These fuel compositions are taught to maintain the cleanliness of intake systems without contributing to combustion chamber deposits.
Aromatic compounds containing a poly(oxyalkylene) moiety are also known in the art. For example, the above-mentioned U.S. Pat. No. 4,191,537, discloses alkylphenyl poly(oxyalkylene) polymers which are useful as intermediates in the preparation of alkylphenyl poly(oxyalkylene) aminocarbamates.
Similarly, U.S. Pat. No. 4,881,945, issued Nov. 21, 1989 to Buckley, discloses a fuel composition comprising a hydrocarbon boiling in the gasoline or diesel range and from about 30 to about 5,000 parts per million of a fuel soluble alkylphenyl polyoxyalkylene aminocarbamate having at least one basic nitrogen and an average molecular weight of about 800 to 6,000 and wherein the alkyl group contains at least 40 carbon atoms.
U.S. Pat. No. 5,112,364, issued May 12, 1992 to Rath et al., discloses gasoline-engine fuels which contain small amounts of a polyetheramine and/or a polyetheramine derivative, wherein the polyetheramine is prepared by reductive amination of a phenol-initiated or alkylphenol-initiated polyether alcohol with ammonia or a primary amine.
European Patent Application Publication No. 310,875, published Apr. 12, 1989 discloses fuels for spark ignition engines containing a polyetheramine additive prepared by first propoxylating and/or butoxylating an alkanol or primary or secondary alkylmonoamine and then aminating the resulting polyether with ammonia or a primary aliphatic amine. French Patent No. 2,105,539, published Apr. 28, 1972, discloses carburetor detergent additives which are phenoxypropylamines which may be substituted with up to five hydrocarbon radicals of 1 to 30 carbon atoms on the aromatic ring. This patent also discloses additives obtained by reacting such phenoxypropylamines with alkylphosphoric acids.